Improvement in treating furnace-slag to convert the same into tiles, slabs



UNITED STATES PATENT OEEIoE.

JOSEPH WOODWARD, OF LEAMINGTON, COUNTY QF WARWICK, ENGLAND.

IMPROVEMENT IN TREATING FURNACE-SLAG T0 CONVERT THE SAME INTO TILES,SLABS, AND BLOCKS.

Specification forming part of Letters Patent No. 221,649, dated November11, 1879; application filed October 13, 1879.

To all whom it may concern.-

Be it known that I, J osEPH'WdoDwARD, of Lcamington, county of Warwick,England. have invented a new and useful Improvement in TreatingFurnace-Slag to Convert the Same into Tiles, Slabs, and Blocks, of whichthe following is a specification.

My invention relates to the utilizing of fur- .nace slag or scoria byconverting it-into tiles,

to a furnace or kiln, where they are subjected to a white heat, or to aheat as intense as possible without causing a refluxing of the slag.

The furnace or kiln is heated before the charging operation, after whichthe air must be excluded by a proper lutin g of all apertures, thesupply of fuel to the kiln being then discontinued.

The tiles, blocks, or slabs are permitted to remain in the closedfurnace or kiln for a length of time (ordinarily from four to sixhours)which may depend upon the size of the tiles or slabs and upon. thecharacter of the slag used. On

removing the tiles or slabs they are permitted to become cool, and arethen ready for use.

The slag by this process of tempering loses its brittle properties, andbecomes so hard and compact thatthe tiles, slabs, or blocks can be usedto advantage in the making of durable pavements, and for many otherpurposes.

Care should in all cases lie-taken to prevent the blocks or slabs frombecoming reduced to a lower temperature than a blood-red color indicatesbefore they are subjected to the greater heat by which the desiredtemper is imparted to them.

The inflammable waste gases of blast-furnaces may be utilized in heatingthe furnaces or kilns.

When slag has been tempered in the manner described it has none of thedark appearance of ordinary slag, but has the aspect and characteristicsof a grayish, compact, hard, and fine grained stone.

When the molds are heated prior to receiving the molten slag, the tile,slab, or block will have the above characteristics throughout; but theuse of chilled molds will result in the production of tiles or slabswith vitreous coatings, and these may be used to advantage in thebuilding of sewers and for other purposes.

It should be understood, however, that when cold molds are used the slagtherein should not be permitted to become cool before the tiles or slabsare placed in the furnace or kiln.

I claim as my invention- 1. The mode described of treating the slag orscoria of furnaces, the same consisting in first casting the molten slagin suitable molds for tiles, slabs, blocks, and other objects, and thenremoving the latter from the molds, and, while they are still hot,subjecting them to a greater heat in a closed furnace, all substantiallyas set forth.

2. As a new manufacture, a slag tile, slab, or block having a grayishappearance, and possessing the characteristics of a very hard, dense,and fine-grained stone, as set forth.

,In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

, JOSEPH WOODWARD.

Witnesses:

CHAS. F. TIETZE, HARRY SMITH.

